Question

Explain the concept of inertia. Write two examples each for the inertia of motion, the inertia of rest, and inertia of direction.

Answer 1

The inability of objects to move on their own or change their state of motion is called inertia. Inertia means resistance to change its state. There are three types of inertia:

1. Inertia of rest:

The inability of an object to change its state of rest is called inertia of rest.

Example:

• When a stationary bus starts to move, the passengers experience a sudden backward push.
• A book lying on the table will remain at rest until it is moved by some external agencies.

2. Inertia of motion:

The inability of an object to change its state of uniform speed (constant speed) on its own is called inertia of motion.
Example:

• When the bus is in motion, and if the brake is applied suddenly, passengers move forward and hit against the front seat.
• An athlete running is a race that will continue to run even after reaching the finishing point.

3. Inertia of direction:

The inability of an object to change its direction of motion on its own is called inertia of direction.

Example:

• When a stone attached to a string is in whirling motion, and if the string is cut suddenly, the stone will not continue to move in circular motion but moves tangentially to the circle.
• When a bus moving along a straight line takes a turn to the right. The passengers are thrown towards the left.